The invention set forth in this specification relates to new and improved loudspeaker and horn structures and/or combinations. On occasion such structures or combinations are referred to as horn loudspeakers.
A wide variety of different so-called loudspeakers are, of course, used to convert electrical energy into sound or sound energy. It is considered that an understanding of the present invention does not require a detailed discussion of all of the various different types of loudspeakers which have been manufactured and used. Such speakers or loudspeakers are normally constructed so as to include a diaphragm of one known type or another which is physically moved directly or indirectly in response to an applied electric signal in order to move adjacent air so that sound is produced. For many years it has been recognized that the relative clarity of such sound can be improved by utilizing a so-called horn adjacent to such a diaphragm.
The horns previously used with speakers have been constructed in many different ways. In a sense, a horn is utilized to couple the sound produced at or about the surface of the diaphragm with the ambient air. In so doing an internal cavity within a horn which is open to the ambient air serves to reflect, direct and to some extent modify the pressure changes within the air constituting the sound so that the sound is directed outwardly from the speaker diaphragm into the ambient air. Depending upon how the horn is constructed, as this is accomplished some sound may be absorbed to a degree by the walls of the horn cavity and to a degree there may be some resonance set up as a result of the shape of the horn cavity and/or as a result of the material used in the horn.
These and various other factors not specifically enumerated are considered to effect the clarity of the sound characteristics resulting from the operation of a horn loudspeaker. These and such other factors are also considered to effect the amount of sound produced per unit of electric power used to drive the speaker. This ratio is considered important since it is normally desired to obtain as great an amount of sound per unit of electric power used as reasonably possible. This is important not only from an economic standpoint but also because many speakers do not operate in the intended manner when comparatively high levels of electric power are supplied to them.
In any horn loudspeaker the primary objective is always to obtain a sound of desirable characteristics, particularly sound which may be regarded as "clear" in the sense that it reasonably corresponds to a sound being reproduced through a loudspeaker. Thus, for example, when the sound of a specific musical instrument is reproduced through the loudspeaker the sound produced by the loudspeaker should be substantially the same as the sound originally produced by the instrument. The sound produced by a speaker or by a horn loudspeaker normally involves one or more sounds of intended frequencies plus a multitude of harmonic tones and a multitude of tones which cannot be reasonably classified, except, perhaps, with reference to the manner in which the original sound is produced.
One problem in any sort of a speaker or horn loudspeaker relates to the complexity of the sound which is obtained at any one time as, for example, an orchestra plays music. In practice the construction of horn loudspeakers which will accommodate and accurately reproduce a multitude of sounds throughout the entire range of sound frequencies capable of being received by the human ear is quite difficult. Because of the problems involved in reproducing a multitude of sounds with clarity, it has been conventional to use a plurality of horn loudspeakers in combination with one another, each horn loudspeaker so used being constructed to be primarily responsive to within a specific frequency range. While this type of expedient is desirable, it is believed that it is desirable to minimize the use of a number of horn loudspeakers together because of the cost of such horn loudspeakers.
From this discussion it is believed it will be apparent that a number of complex and interrelated factors are involved in connection with the construction and operation of loudspeaker and horn structures or horn loudspeakers. Although such devices or combinations are well known, it is believed that there exists a continuing need for new and improved horn loudspeakers having a desired degree of clarity which can be operated utilizing a comparatively minimal amount of electric power in order to produce a comparatively maximum amount or intensity of sound and which can achieve these results over a reasonably wide frequency range.